Hidden Swift Concurrency Bugs

Swift’s concurrency model gives us powerful tools like async/await, actors, tasks, and structured concurrency. But some of the hardest bugs are the ones the compiler allows.

So what do we do about swift concurrency bugs that compile just fine?

In this meetup, we’ll look at real-world concurrency problems that can make an iOS app behave unpredictably even when the code appears correct.

We’ll cover things like:
• Tasks that outlive the screen or object that created them
• Cancellation that never actually gets handled
• Accidentally doing expensive work on the MainActor
• Actor isolation and shared mutable state
• Race conditions that only appear under load
• Unstructured Task {} usage
• Why code that works in testing can still fail in production
• Practical patterns for making concurrent code easier to reason about

We’ll work through some small examples and look at ways to identify and prevent these problems before they become difficult production bugs.

The goal is not just to learn Swift Concurrency syntax, but to understand how concurrent Swift code actually behaves when things go wrong.

This will be a presentation by our member Ross.

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It will take place in the Seminar Room at the La Jolla Riford Libary for 1.5 hours which has a capacity of 40 people. There is parking lot at the library and parking on the street in the surrounding area.

Everyone interested is welcome: app developers, business owners, entrepreneurs, and investors. The idea is to grow this group to be a great networking hub where people can meet each other for projects and/or friendships.